Dielectric properties of epoxy-dielectrics-carbon black composite for phantom materials at radio frequencies

Abstract

In order to develop new dry phantom materials that can simulate the effect of electromagnetic wave on human tissues, the dielectric properties of the phantom materials composed of dielectrics, carbon black, and epoxy resin were investigated. For dielectrics/epoxy composite, the dielectric constants increased with the content of dielectric powder and were independent of frequency at the measured frequency range. The dielectric constants and conductivity of carbon black/epoxy composite also increased with the carbon black, but it showed the frequency dependence that the complex dielectric constants decreased with increasing frequency. The dielectric constants and conductivity corresponding to human tissues could be obtained by combining the frequency dependence of carbon black/epoxy composite with the dielectric properties of dielectrics/epoxy composite and by adjusting the composition ratios of carbon black, dielectrics, and epoxy. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 1294–1302, 2000

Structural, mechanical, thermal, and electrical properties of carbon black reinforced polyester resin composites

“…However, the difference in σ dc and σ ac values at a particular CB content are due to two different measurements techniques. The observed electrical properties of some of the resulting composites can be applied to the human phantom materials, as also suggested elsewhere …”

“…This result suggests a development of frequency dependent ε value after CB loading, and the increasing CB content makes these differences larger. The CB is reportedly a semiconducting material and not dielectric by itself . If CB is covered with insulator like PR, it may behave as a dielectric material by generating space charge polarization at the interfaces.…”

Preparation and Microwave Absorption Properties of Ti3AlC2 Synthesized by Pressureless Sintering TiC/Ti/Al

“…The expression shows that the enhanced electrical conductivity of the mixtures could be considered as a dominating factor for the increase of ε″, which is due to the increased conductivity of the mixture with the enhancement of Ti 3 AlC 2 volume fraction according to the percolation theory . Furthermore, as the interfacial polarization is more easily induced at lower frequency and the displacement current significantly lags behind the buildup potential as the frequency increase, it is reasonable that both ε′ and ε″ decrease with increasing frequency and exhibit a visible frequency‐dependent dielectric response …”

Mechanical and dielectric properties of short‐carbon‐fibers/epoxy‐modified‐organic‐silicone‐resin as heat resistant microwave absorbing coatings

“…These absorbers possess favorable absorption performance and are widely used in the applications aforementioned, but they can be used only at room temperature. Another kind of microwave absorption coatings, which is composed of matrix and dielectric absorbers, such as short carbon fibers, carbon black, and carbon nanotube, could be used at high temperatures. However, the application of this kind of coatings in the high temperature environment is still challenged taking account of the weak adhesion between the coating and the metal substrate caused by the thermal expansion coefficient mismatch and the unsatisfactory absorption performance as compared to the coatings containing magnetic lossy absorbers.…”

“…Nevertheless, C sf /epoxy modified organic silicone resin coatings on metal substrate, used as high temperature microwave absorption material, have been reported rarely. According to the available data, the coatings with lower content short carbon fiber can obtain the same complex permittivity as the coatings with a large number of carbon black and carbon nanotube. The better frequency dependence of the coatings with C sf also favors the absorption performance.…”